Here's why:

* DNA Code: DNA is made up of four bases: A, T, C, and G. These bases code for amino acids, which are the building blocks of proteins.

* Redundancy: The genetic code is redundant, meaning that multiple codons (sequences of three bases) can code for the same amino acid.

* Silent Mutations: A silent mutation occurs when a change in a single base in a codon does not change the amino acid that is coded for. This is because the new codon still codes for the same amino acid.

* No Effect: Since the amino acid sequence of the protein remains unchanged, the protein functions normally, and there is no observable effect on the organism.

Example:

Imagine a codon coding for the amino acid "Alanine" is GCA. If a mutation changes it to GCG, it's still coding for Alanine. This is a silent mutation.

Important Note: While a silent mutation may not have an immediate effect, it can potentially influence the organism's evolution over long periods.